Venting for mold cavities in centrifugally casting



'lill/Illa.

H. J. WOOCK Filed Jan. 22, 1943 VENTING FOR MOLD CAVITIES IN CENTHIFUGALLY CASTING June 1948.

INVENTOR. 9

ATTORNEY.

Patented June 1, 1948 UNITE!) STATES EOBMOLD GAVITIESzIN CENTRIFUGALLYQASTING .7 Claims. 1

'This 'invention :relates fto `'venting theimoldr-oavities fin l.centrifuga-1 casting operations it may be considered as diuisionahoffthe `sulejrectimatter disclosed in :my :applications .Seri-al :Numbers473, :213, :now abandoned, :and 4v173;21'4 fnow .-Paterxt :No. Zei-153620, `file-.c1foreven date rherewith.

In the above-numbered applicationstlfhaveidisclosed a casting apparatus wherein themnldicav- *ities are formed in individual r'dies each of 'which is .composed of separable .aparts :such as fa Icope and :a drag. The nope and fdrag Jof -each Fdie secured Eto zc'one and drag retaining ielements 'which Aare `likewise fseparable kso that when the 'copie fand drag :retaining elements :are iopened the 'pants of 1the 4'die fare ,opened nor separated thereby. The feope drag .retaining elements 'are together l.rotatable "about a :vertical central axis 'ooincident with which lis fa :central ignoring gate imm which runners lead `to .the `:mold `cavities in fthe individual Iiies. 'inasmuch `as lthe :metal nrother materialmnatiispoured into 'the pouring gate frs .'c'ansed'to .enter the arnold navitres eat iiiigh velocita! 'due ite :the icrentrifugal .action fdeueloped thereon :sit :is Important rthat :an adequate arent f-lre .provided ifm' '..theimo1d.eavity, e'otherwise the fair '.cr gas .initiaiiiy present .ian the nno'd `.cav-ity :fcannot escape it'reretrnm .fand 'would ntirerw'ise produce an'nnonlzets :the fcastnrg.

Atprimal'y mbientiof "the apreseut wnventron is "to provide 'anneans 'and methndwhereby feentriiugalmmltdzhavingmrildavitessra'diallyzsnacedfrnm tire 'axis has fthe :metal tied thereto by 'the emmers :trom s.the central moi-ning gate in 'such a :manner :that the air :or ;gas nitially :in the imold will abe 'expelled :by .the incoming metal inward :a Went *withmxt causing it .te be 'iincluiedfinrthelmetal.

.Another eb'iect mf tire :invention .is ato :provide a, roentri'ugafl 'mold iraving radially sglaeed 'meid cavities Vwherein tlrere1is :a :vent for `ea-'oh :cavity so zamngc dhat 'fire mold v"avity will irst lled 'hyithe rinconing metal :so ias fto fuornplete'ly expel the air theretrm'noefnreithemeta :isicaused `to :enter theventmg message.

'StiIl :a :further @object tithe invention :is `vto .prende a .centrifugal .fm'old ihavirrg za. :cope :and .a 'time separable @from :each other fon ra martine plane 'wherein the manners .reading fto the mold cavities 53nd thfe'ven't @passages 'l'eadirrg rthererrom will -`be ziocatedmn 'or #adjacent :the parting zrlane 'se mtal solidi-557mg iin the runners an'iwen't passages will'not loekftrfe-cone anivag "against separation. v

`detailed description and specifically pointed out lin .the appended claims, reference .is :had to `the accompanying .drawings for an illustrative em- `loodiment of -the invention, wherein:

Figure 1 .-is 'a top .plan `View -of .a .centrifugal Jmolding machine A.illustrating .the .mold cavities .as Y.being .equipped with .runners ,and vents .in .accordance with Ythe `present linvention, apart .of `this View illustrating ythe Vmachinebeing :broken .away and shown in :horizontal section; .and

Eg.-2 Ais apartial .view 1verticalsection taken substantially upon ftheflinef2-2 -upon Fig. l.

. Refervingto .thenccompanyingdrawingsavhere- .insimilar reference =eharaot-ers :designate .similar .parts throughout, -the .upper circular iplate .It together with :associated .structure .constitutes a cope retaining element and the lower plate .Ll together with associated structure constitutes a drag .retaining element. .SIlhe lower :plate -rM `is supportedon .a central vertical shaft .i 2 which can be .raised-and .lowered to effect a AVerticalsliding of :the drag retaining .element :H -on rods i3. The .cope retaining element .and drag retaining elementtogether with theFrod-s 43 fandthe sh aft l2 are rotatable Vin unison about the vertical central taxis fcoincident -with the .longitudinal Ycentral :axis throughtheslrat -|2. Inithe cope retaining element ri there @is ireplaoeably secured .a gate providing member 44 :having fia .gate I5 coincident `wthtire `:axisof rotation. A lbarrier plate L6 is secured `to the drag :retaining element H and `provides fthe gbottom :for .the .gate #.5 .as well as :for the runners `I 1 :leading'thereirom .fand Jvent passages I3. ilhegate providing :member lfd and .the barrier @plate elr .arefnormallyiintabutment vbut are #separable from eachother f on a 'parting 'plane indicated 4at 49.

Theimold foaviti-es 20 :fare formed V.in .individuel dieszeaohzof whichmay eompriseza cope .2J .and a drag 22. The copes .of .the .individual dies :are secured to the .cope 4.retaining `element .Ml 1althoug'hltheremaybe intervening spacers Z3. Sim 'ar'ly the drags 22 are secured lto vthe [drag retaining element Il althoughthere may'be inter- Vening spacers 21. The spacers are employed 'so :thattlre parting *lines or parting planes 25 of the individua-1 Adies will V:be tin the `sanne jplane with "the "parting qplane |-9 between the gate proviingmenib'er :F4 vand theibarrier-'plate im. The runners I1 are 'preieralily formed `on the 4:bottom surface ^of tire gate providing member "I4 "ab though :these runners may, :if *desired -`be x`formeel in l"tllet'op Vof the barrier `plate "l E. 'all 'events they should "be exposed on the parting piane which 'wm "be 'made manifest 'in 'the 'rollownrg 65 Continuationsdftheserunners'are 'formedin "the dies, such continuations being indicated at 26. These continuations lead to the rear or trailing inner corners of the mold cavities. The exact points where the extensions 26 communicate with the mold cavities will vary considerably depending upon the size and shape of the mold cavity and its position in the die. The exten-sions however should communicate with the trailing side of the mold cavity. Thus, if the mold is considered as rotating in a clockwise direction as viewed in Fig. 1, the extensions 26 communicate with the mold cavities at their rear sides.

The vent passages I8 are likewise shown as being formed on the bottom surface f the gate providing member I4 so as to be in the same plane with the runners I 7. This arrangement is not essential as the vent passages may be formed' in the top surface of the barrier plate I6. However, these passages should also be exposed on the parting plane I9. They communicate with vertical apertures 2'! leading to the atmosphere, it being understood that the dies are slightly spaced from one another as clearly shown in Fig. 1. Ordinarily, it is not necessary to form the apertures 21 .'ith any draft, but if any draft is formed in these apertures or in the walls of the runners or the vent passages the draft should be such as to enable the barrierplate I6 which becomes a part of the drag of the mold to separate from the cope. The vent passages I8 have extensions 28 formed in the dies which communicate with the mold cavities 20 at their forward inner corners considered in relation to the direction of rotation of the mold. 29 indicates a shield which surrounds the rotatable mold and which can be lowered on opening the mold to enable removal of the finished castings.

In pouring the mold, the mold is first started rotating and the molten metal is introduced through the central gate I while the mold is rotating. This is fed to the individual mold cavities through the runners or feeder gates I`I and their extensions 26. As the metal passes out through these runners it is subjected to centrifugal action and is constantly being accelerated in a circular direction as it progresses radially from the center of rotation. The metal that is fed into the mold cavity quickly lls the mold cavity toward the extensions 28 of the vent passages I8. The initial air or gas that may be in the mold cavity is thus expelled by the incoming metal without any tendency of its being included or mixed with the metal filling the mold cavity which would otherwise result in blow holes and fissures therein. Ultimately, the mold cavities 20 are completely filled and any excess metal may iiow out through the inwardly extending vent passages and may even ll and slightly overflow from the apertures 21. When the metal has solidified the mold is stopped rotating and the vertical shaft I2 is lowered lowering the master drag I I and the individual die drags 22 from the master cope and the individual die copes.

Inasmuch as the vent passages and the runners or feeder gates are located on the same plane and are exposed on the parting planes of the cope and drag retaining elements and the individual die copes and drags that metal which may solidify in the vent passages and runners will not lock the parts of the mold against separation. When the mold is opened the shieldZS is lowered or otherwise removed to enable the removal of the casting which is usually in the form of a plurality of castings connected together in the form of a large spider, the connections being provided by the 4 metal remaining in the runners or feeder gates I1. After the casting has been removed the mold can be again closed and the casting operation repeated.

It will be appreciated that by the present invention it is possible to centrifugally cast by running molten metal centrifugally into rotating mold cavities and enable the air or gas initially present in the mold cavities to escape therefrom without being included in the metal of the casting. Furthermore, metal soldifying in the runners or vent passages or both does not lock the cope and drag retaining elements against separation.

Although I have illustrated each individual die as being formed of merely a cope and drag it will be understood that the dies may be required to be made of three or more parts in order to effect or enable their being opened to remove the completed casting. If the die is formed of three or more parts the extensions 26 and 28 should be formed on one of its opening or parting planes wherever they may be located.

Various changes may be made in the details of construction without departing from the spirit or scope of the invention as defined by the appended claims.

I claim:

1. A centrifugal mold having mold cavities rotatable about a central axis of rotation and formed in parts separable upon a radially extending parting plane, there being inlets to the mold cavities exposed on the parting plane, and vents from the mold cavities exposed on the parting plane, the inlets communicating with the trailing sides of the mold cavities and the vents communicating with the leading sides 'of the mold cavities.

2. A centrifugal mold having mold cavities rotatable about a central axis 'of rotation and formed in parts separable upon a radially extending parting plane, there being inlets to the mold cavities exposed on the parting plane, and vents from the mold cavities exposed on the parting plane, the inlets communicating with the trailing sides of the -mold cavities and the vents communicating with the leading sides of the mold cavities and extending inwardly therefrom.

3. A centrifugal mold having cope and drag retaining elements rotatable about a central axis. a gate providing member on the cope providing a central gate, means on the drag retaining element closing the bottom of the gate and defining a radially extending parting plane, means providing mold cavities having copes and drags secured to the cope and drag retaining elements having a parting plane in the same plane' with the first mentioned parting plane, runners leading from the gate to the mold cavities exposed on said parting plane, and vents leading from the mold cavities to atmosphere exposed on the parting planes, the runners leading to the trailing sides of the mold cavities and the vents leading from the leading sides thereof.

4. A centrifugal mold having mold cavities rotatable about a central axis of rotation and formed in parts separableupon a parting plane, there being inlets to the mold` cavities and vents from the mold cavities the inlets communicating with the mold cavities adjacent their inner sides and near the trailing sides thereof and the vents communicating with the mold cavities adjacent their inner sides and adjacent the leadingv sides thereof. .y

5. A centrifugal mold having mold [cavities rotatable about a central axis of rotation and formed in parts separable, upon a parting plane,

there being inlets to the mold cavities and vents from the mold cavities the inlet communicating with the mold cavities adjacent their inner sides and near the trailing sides thereof and the vents communicating with the mold cavities adjacent their inner sides and adjacent the leading sides thereof, the vents and inlets being exposed on the parting plane so as not to interfere with opening of the mold.

6. A centrifugal mold having mold cavities spaced from the axis of rotation of the mold, a central gate, runners leading from the gate to the mold cavities and communicating therewith on the innermost sides of the mold cavities, and vents for the mold cavities also communicating therewith on their innermost sides, said vents being arranged in advance of the runners leading to their respective mold cavities in respect to the direction of rotation of the mold.

7. A centrifugal mold having mold cavities spaced from the axis of rotation of the mold, a central gate, runners leading fro-m the gate to the mold cavities and communicating therewith on the innermost sides of the mold cavities, and vents for the mold cavities also communicating therewith on their innermost sides, said vents being arranged in advance of the runners leading to their respective mold cavities in respect to the direction of rotation of the mold, said vents and runners being exposed on the parting plane of the mold so that if they become filled with the material cast it would not prevent opening of the mold.

. HERBERT J. WOOCK.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS OTHER REFERENCES The Principles of Iron Founding by Richard Moldenke, McGraw-Hill Book Co., New York,

second edition, 1930, pages 548 and 549. 

